Sacral doming progression in developmental spondylolisthesis: a demonstrative case report with two different evolutions.

Abstract

Demonstrative case report of two different evolutions in developmental spondylolisthesis. To our knowledge spontaneous sacral doming reconstruction and healing has never been previously reported. Presentation of two cases with developmental spondylolisthesis and no sacral dome that had at the beginning a similar presentation and finally evolved in different ways. Initially, both cases were without sacral dome. In the first case, sacral dome appeared and completely healed in presence of a stable elongata pars and stable spondylolisthesis. In the second case, apparition, progression of sacral dome, rolling up of L5 and spondylolisthesis occurred in the presence of lytic defect in the pars. Sacral doming is secondary to L5 abnormal position regarding to S1. The mechanism of sacral doming looks like as an osteochondritis phenomena. Loss of support of the sacral plateau by sacral rounding may induce high grade spondylolisthesis.